<template>
  <el-select ref="treeSelect" :value="valueTitle" :clearable="clearable" @clear="clearHandle">
    <el-input v-model="filterText" class="selectInput" :placeholder="placeholder"></el-input>
    <el-option :value="valueTitle" :label="valueTitle" class="options">
      <el-tree
        id="tree-option"
        ref="selectTree"
        :accordion="accordion"
        :data="options"
        :props="props"
        :node-key="props.value"
        :default-expanded-keys="defaultExpandedKey"
        :filter-node-method="filterNode"
        @node-click="handleNodeClick"
      ></el-tree>
    </el-option>
  </el-select>
</template>
<script>
  export default {
    name: 'ElTreeSelect',
    props: {
      /* 配置项 */
      props: {
        type: Object,
        default: () => {
          return {
            value: 'id', // ID字段名
            label: 'title', // 显示名称
            children: 'organizationTreeVo', // 子级字段名
          };
        },
      },
      /* 选项列表数据(树形结构的对象数组) */
      options: {
        type: Array,
        default: () => {
          return [];
        },
      },
      /* 初始值 */
      value: {
        type: Number,
        default: () => {
          return null;
        },
      },
      /* 可清空选项 */
      clearable: {
        type: Boolean,
        default: () => {
          return true;
        },
      },
      /* 自动收起 */
      accordion: {
        type: Boolean,
        default: () => {
          return false;
        },
      },
      placeholder: {
        type: String,
        default: () => {
          return '检索关键字';
        },
      },
    },
    data() {
      return {
        filterText: '',
        valueId: this.value, // 初始值
        valueTitle: '',
        defaultExpandedKey: [],
      };
    },
    watch: {
      value() {
        this.valueId = this.value;
        this.initHandle();
      },
      filterText(val) {
        this.$refs.selectTree.filter(val);
      },
    },
    mounted() {
      this.initHandle();
    },
    methods: {
      // 初始化值
      initHandle() {
        if (this.valueId) {
          // this.valueTitle = this.$refs.selectTree.getNode(this.valueId).data[this.props.label]; // 初始化显示
          this.$refs.selectTree.setCurrentKey(this.valueId); // 设置默认选中
          this.defaultExpandedKey = [this.valueId]; // 设置默认展开
        }
        this.initScroll();
      },
      // 初始化滚动条
      initScroll() {
        this.$nextTick(() => {
          let scrollWrap = document.querySelectorAll('.el-scrollbar .el-select-dropdown__wrap')[0];
          let scrollBar = document.querySelectorAll('.el-scrollbar .el-scrollbar__bar');
          scrollWrap.style.cssText = 'margin: 0px; max-height: none; overflow: hidden;';
          scrollBar.forEach(ele => (ele.style.width = 0));
        });
      },
      // 切换选项
      handleNodeClick(node) {
        this.valueTitle = node[this.props.label];
        this.valueId = node[this.props.value];
        this.$emit('getValue', this.valueId);
        this.defaultExpandedKey = [];
        if (!node.children || !node.children.length) {
          //补录选择完选项不能收起
          this.$refs.treeSelect.blur();
        }
      },
      // 清除选中
      clearHandle() {
        this.valueTitle = '';
        this.valueId = null;
        this.defaultExpandedKey = [];
        this.clearSelected();
        this.$emit('getValue', null);
      },
      /* 清空选中样式 */
      clearSelected() {
        let allNode = document.querySelectorAll('#tree-option .el-tree-node');
        allNode.forEach(element => element.classList.remove('is-current'));
      },
      filterNode(value, data) {
        if (!value) return true;
        return data.deptName.indexOf(value) !== -1;
      },
    },
  };
</script>
<style lang="scss" scoped>
  .el-scrollbar .el-scrollbar__view .el-select-dropdown__item {
    height: auto;
    max-height: 274px;
    padding: 0;
    overflow: hidden;
    overflow-y: auto;
  }
  .el-select-dropdown__item.selected {
    font-weight: normal;
  }
  ul li >>> .el-tree .el-tree-node__content {
    height: auto;
    padding: 0 20px;
  }
  .el-tree-node__label {
    font-weight: normal;
  }
  .el-tree >>> .is-current .el-tree-node__label {
    color: #409eff;
    font-weight: 700;
  }
  .el-tree >>> .is-current .el-tree-node__children .el-tree-node__label {
    color: #606266;
    font-weight: normal;
  }
  .selectInput {
    padding: 0 5px;
    box-sizing: border-box;
  }
</style>
